Art of making crossing sheets of plywood panels



Oct. 16, 1934.v G H QSGQQD ART OF MAKING CROSSING SHEETS OF PLYWOOD PANELS Filed May 3l, 1953 Patented Oct. 16, 1934 PATENT oFFicE ART F MAKING CROSSING SHEETS 0F PLYWOOD PANELS George H. Osgood, Tacoma, Wash.

Application May 31, 1933, Serial No. 673,755

'somma My invention relates to the building up of plywood panels and has special reference to the means of forming the internal cross-grained layers thereof. These cross-grained layers are known in the trade as the core"and the crossbands in accordance as to whether the particular layer is the central layer or core, or is one of the other cross-layers in ilve, seven, or eleven ply panels. All these several layers are arranged with their grains running substantially at rightangles to the direction of the grain in the face or outer layers of the panel and are designated hereinlas crossings In all plywood mills which are producing panels, for doors or other uses. particularly in mills using heavy face veneer panels of low price materials, such as ilr, pine', gum, spruce, etc., the trimmings from the veneer sheets must be thrown away because they are very narrow (from two to five inches) and if these trimmings were used in building pp the core or the cross-bands the productiomof the mill would be curtailed to a. point where it is more economical to throw away these trimmings than it would be to use them, because each piece would have to be separately handled and carefully placed in position, therefore, in practice, the crossings are usually specially out of very substantial width and the above referred to trimmings are wasted. If, too,

30. one should attempt to save the trimmings by taping the adjacent sideedges of the strips together, the cost of the paper or cloth tape and of the labor in handling the pieces would be greater than the value of the salvaged stock.`

Further, in the practice of hand manipulation of these crossings it is found that the operator, in building up the core or the cross-band, will often permit a space to exist between two adjacent crossing strips, thereby leaving an objectionable void in the panel being formed, or he will permit the edge of one crossing to overlap that of the other, thereby preventing them from lying flat and causing an unevenness of pressure when the 5 panel is in the press, thus seriously weakening the hold of the glue and otherwise making an imperfect panel.

It is the object of this invention to permit the economical use oi the otherwise wasted narrow trimmings of veneer wood and at the same time to prevent or greatly reduce the of forming imperfect panels from the improper placing of the crossings relatively to each other.

I attain these and other objects by the use of any suitable machinery as, for example, the

machine illustrated in the accompanying drawing, in which- Fig. 1 is a side elevation of a machine adapted to produce my improved crossing sheet, said machine being shown largely diagrammatically; Fig. 2 is a front elevation thereof and Fig. 3 is a plan view4 of a portion of crossing sheeting formed by such a machine and from which the desired length of crossing for the plywood panel, may be cut.

Similar numerals of reference refer to similar parts throughout the several views.

Briefly, my objects are attained by passing the successive crossing strips, before they are coated with glue, through a machine which will fasten them together into one continuous sheet by gluing each strip to a pair of continuous strings or tapes which pass across each strip in lines parallel with the grain of the ultimate face plies of the panel and at right-angles to the grain of the said respective crossing strips. 'Ihe sheet thus formed is then cut into lengths equal to that of the panels and may then be run through the glue spreader and .incorporated into the panels.- It is evident, then, that each layer of crossing is handled as a single piece and yet comprises a very large number of separate pieces salvaged from waste material.

The machine is formed of two complementary parts, each of which applies the tape or string to each crossing strip simultaneously as it is fed, in crossways position, therethrough, one said part being normally fixed in position and the other part being adapted to be adjusted-in position, relatively to the fixed part, in order to accommodate strips adapted for panels of various widths.. Since these two parts are similar the description of one will be understood to apply to the other.

The base on which both .said parts are mounted comprises a pair of suitable foundation beams 1 which extend across the machine and to which the said parts are secured in proper position thereon by any suitable means. 'I'he pedestal 2 is secured to the base 1 and carries a table 3 which has extensions 4 in both forward and rearward directions. 'I'he table 3 carries asuitable feed belt or chain 5, usually comprisingv a fabric belt with a soft rubber face, said belt being endless and being driven by any suitable means. The belt 5 travels on top of the table 3 and over suitable rpulleys 6 at the ends of the extensions 4 and then returns under the table. A gauge 'I is adjustably mounted on'the fixed table 3 and forms a stop no 2 against which the ends of the successive crossing strips are placed when the said strips are placed on the traveling belt 5.

A head 8 is mounted on the top of the pedestal 2 to one side, and is provided with an overhanging arm 9,-which carries, at its outer end, a roll of tape, or of string, 10 and which also carries a depending body 11 which has forward and rearward extensions 12, which in turn carry a series of pressure rollers 13. These extensions 12 also carry, on the front section, a tape moistening pot 14 and, at the front end, a glue pot 15 with a suitable glue-applying wheel 16. When cloth or paper tape is used it is often already coated with glue and therefore it is only necessary to dampen it before it touches the veneer crossing strips at the first roller 13, and no glue is then fed from the pot 15, but if a soft, loosely twisted string is used, the glue from the pot 15 is applied in a narrow band to the successive strips of crossings by the wheel 16, as they pass under the overhanging extensions 12, and the string is brought down on top of this narrow band of glue by the rst roller 13 and is pressed thereon by the succeeding rollers 13. The glue used is preferably of a quick-drying type. When the panel is made up the tapes or strings do not add appreciably to its thickness.

The resulting crossing sheet 17, which is made up of many strips 18 of plywood or other thin wood all fastened together side by side by the strings or tapes glued thereto, cornes from the machine in one continuous sheet. As it leaves the table `xtension 4 at the rear, it is transferred to a measuring table 19 and is cut by the al knife 20 to the desired length. This cut sbggis then handled as a unit and ltreated as though it were a single piece of core or crossband. When the panel is to be built up this length of crossing is passed through the glue spreader and applied between the other sheets of plywood in the usual manner.

Having described my invention, what I claim and desire to secure by Letters Patent, is:-

1. The method of forming a sheet of crossing for plywood panels by feeding a plurality of narrow pieces of veneer successively through a machine, each said narrow piece of veneer lying across the path of its motion and being as long as the width of the plywood panels, and lying side by side in contact with each other; applying a plurality of strips of glue to each said narrow piece of veneer as .they successively pass through the machine, said strips of glue being Iparallel with the path of motion of the veneer pieces; feeding and pressing a plurality of continuous loosely twisted 'strings from the machine onto the strips of glue as the vpieces of veneer pass through the machine, each said string crossing successively all the pieces of veneer and being secured thereto by the glue in which it is pressed; and cutting said sheet transversely into lengths equal to the lengthof the plywood panels.

2. The method of producing a sheet of crossing for a plywood panel from a plurality of narrow pieces of veneer by placing the pieces side by side and in contact with each other, each said narrow piece of veneer being as long as the width of the plywood panel; applying a plurality of narrow strips of glue to the surfaces of each said narrow piece of veneer, each strip of glue being continuous and passing successively entirely across each said narrow piece of veneer at rightangles to the grain thereof and to their abutting sides and crossing all the joints in the sheet; and pressing a loosely twisted string in each said strip of glue while the glue is wet, each said string crossing successively all the pieces of veneer and being secured thereto by the glue in which it is pressed.

GEORGE H. OSGOOD. 

